public function SendData():void {
    var myData:URLVariables = new URLVariables();

    myData.update = "true";
    myData.score_humans = MasterManager.gameManager.scoreHumans;
    myData.score_creatures = MasterManager.gameManager.scoreCreatures;

    var myRequest:URLRequest = new URLRequest("http://not-a-real-web-server.com/data/testgame.php");

    myRequest.data = myData;
    myRequest.method = URLRequestMethod.POST;

    var loader:URLLoader = new URLLoader();
    loader.dataFormat = URLLoaderDataFormat.VARIABLES;
    loader.addEventListener(Event.COMPLETE, OnSendDataComplete);

    try {
        loader.load(myRequest);
    } catch (error:Error) {
        trace ('Error: unable to load the document.');
    }
}

public function OnSendDataComplete(e:Event):void {
}

<?php

if (isset($_POST['update'])) {
    $dbhost = 'xxx.xxx.xxx.xxx';
    $dbuser = 'bogususer';
    $dbpass = 'boguspassword';

    $mysqli = new mysqli($dbhost, $dbuser, $dbpass, 'test_game_table', 3306);

    if ($mysqli->connect_errno) {
        echo "Failed to connect to MySQL: (" . $mysqli->connect_errno . ") "  . $mysqli->connect_error;
    }

    $score_humans = intval( $_POST['score_humans'] );
    $score_creatures = intval( $_POST['score_creatures'] );

    if ($score_humans >= 0 && $score_creatures >= 0) { // Error-check: No negative values
        $strquery = "update stats";

        $strquery .= " set score_humans = score_humans + " . $score_humans;
        $strquery .= ", score_creatures = score_creatures + " . score_creatures;

        $strquery .= " where id = 1";

        $strquery = $mysqli->real_escape_string($strquery); // Even though it should be clean, sanitize it anyways.

        $mysqli->query($strquery);

        echo "received=true";
    }
}

echo "Hello there!";

?>